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Any protein will have evolved to have an optimum pH that matches the environment it is most commonly found in. This does mean that not all proteins have an ideal pH between 4 and 8. For example, almost all eukaryotic cells contain digestive enzymes that operate best at very low pH and not very well at pH 4-8, so that they won't digest their own cells, which will usually be at pH 7.
Whatever the ideal pH happens to be, the reason for it is always the same:
* Proteins fold into particular shapes that are vital for their function. * The shape a protein will fold into is determined by its amino acid sequence, since different amino acids have different properties. * Each amino acid has a 'side chain' sticking out of the main polypeptide chain, which will have specific chemical properties capable of forming certain interactions with other amino acids in the protein (as well as with water and other molecules).
* It is these intramolecular forces (interactions between different amino acids within a protein) that are responsible for producing and maintaining the shape of the protein. The forces are:
* Hydrogen bonds - weak bonds between slightly positively charged hydrogen and slightly negatively charged atoms (such as oxygen). * Electrostatic interactions - weak attractive forces between charged regions of the protein, including only small charges resulting from polar bonds. * Disulphide bridges * Hydrophobic interactions
* Hydrophobic interactions are not sufficient to hold a protein in a particular shape, only to pull the protein into a ball to help it fold into the correct shape. * Hydrogen bonds and electrostatic interactions are dependent on interactions between charges. pH is a measure of the concentration of hydrogen ions, which are positively charged. If there were more hydrogen ions in the solution than the protein was designed for, these ions would compete for the interactions holding the protein together, as well as protonating groups that need to be deprotonated to form important intramolecular interactions (eg nitrogen). Equally, if there were too few hydrogen ions in the solution, the same interactions would disrupted by the relatively high concentration of hydroxide (OH) ions, and important protonated groups may become deprotonated.
* Disruption of the interactions in either case will lead to some of the protein losing its ability to be held in a certain shape, which then reduces it's catalytic activity (as catalytic activity relies on the shape). The loss of activity will be proportional to the extent of the disruptions, which will in turn be proportional to the extent of the change in pH. * Disulphide bonds would also be reduced (broken) at very low pH. * Therefore, all proteins have a pH at which they have been designed to work that they will work very well at. The further away from this pH the solution gets, the more of the proteins will be effected by the change, until eventually they are all completely denatured. This concept is similar to the collision theory, in that a small change in pH will reduce activity, but not significantly, because very few of the increased hydrogen/hydroxide ions will actually be competing for the intramolecular interactions at any one time. In the specific case of pH being between 4 and 8, this is because most cells have an interior pH of between 4 and 8, so a lot of proteins need to operate best in this range (usually pH 7).
Wiki User
∙ 14y ago
Wiki User
∙ 12y agoenzymes are_" a substance produced by a living organism that acts as a catalyst to bring about a specific biochemical reaction"_taken from wikipedia_
Enzymes help tendorize meat. enzymes help digest food.
I'm not really sure exactly why at PH of 7.
Saliva...I belive, has enzymes to rip apart fats to make them easier to digest.
If you put a saltine craker in your mouth,eat and swallow, wait a long while before eating or drinking and the saliva breaks down the starches to sugar.
saliva is about the same consistency of water(which is 7 on the pH scale)
Try reading a science book though. I'm not sure.
Wiki User
∙ 10y agoThe solution is neither acidic or basic
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Which organ secrets enzymes that are active at a low pH?
The stomach secretes protease enzymes that work best at a pH of around 2.
What pH do neither enzymes work in?
at a ph of 13
What factors affect the activity of enzymes?
Enzymes work best in the pH and temperature that they are " designed " for. A pepsin enzyme works best in the low pH environment of the stomach, while amylase works best at mouth temperature and ~ 7 pH. Heat and out of range pH can denature enzymes and not only affect their activity but inactivate them.
Why do different enzymes have different optimum pH?
Enzymes only work best at a certain pH. This is called an optimum pH for that enzyme. An example is the enzymes found in the stomach. The pH found there is very acidic (around pH2). If this same enzyme was in another part of the body it would either not work well or maybe not at all.The proper pH keeps the protein shape of the enzyme. Anything above or below that can stop it or even denature it. When it is denatured, it will loose the shape it has to be in to work. If you have a screw you need to remove from something, the proper screwdriver is necessary or you will strip the head (damage) the screw.
Will enzyme activity be higher or lower if the pH is high?
Yes it does. Enzymes increase rate of reaction as the pH level increases but enzymes work best at optimum pH. If pH level still increase, then enzyme will become denatured and rate of reaction once again decreases.
Can enzymes work over a broad range of PH levels?
Most enzymes work best at a certain pH, however there are some enzymes that can operate over a broad pH range.
Enzymes work most effectively at?
Enzymes work most effectively when they are at their optimal temperature and pH.
Are pH level and enzymes related?
Most enzymes only work in a certain pH range; pH is not dependent on the presence of enzymes, however.
What pH does amylase works best with?
Most human enzymes work at a optimal pH of 7.4, but other enzymes work at many different pH ranges, for example Pepsin works best at an optimal pH of 2.6 and Trypsin works best at an optimal pH of 7.8.
Which organ secrets enzymes that are active at a low pH?
The stomach secretes protease enzymes that work best at a pH of around 2.
Do enzymes work best at a narrow PH range?
I love halo 3
What pH do neither enzymes work in?
at a ph of 13
Can enzymes function at any pH?
No. They function best at the pH corresponding to their usual/intended environment. For example, pepsin, present in the stomach, which is highly acidic, functions best at acidic pH, while trypsin, secreted into the duodenum together with basic bicarbonate, functions best at moderately basic pH. This is true also within subcellular compartments: the optimal pH of lysosomal enzymes is acidic, matching the acidic proteolytic environment inside the lysosome. That said, most enzymes present in the cytosol (~neutral) and blood (~neutral) function best around neutral pH.
What is meant by the statement enzymes have optimum operating ranges?
That they work best in the right pH and temperature they were made to work in. Amylase works best in the mouth's pH of about 7, while pepsin works best at a much lower and acidic pH.
How can enzymes be inactived?
All enzymes work best at a certain temperature and pH. They also need a substrate to work on. A change in pH or temperature will inactive it by denaturing it. If the substrate is very low in quantity or is absent, the enzyme will be inactive.
How does substrate concentration and pH affect enzymes?
Substrate concentration will affect enzymes because substrates are specific to enzymes. The pH will affect enzymes because certain enzymes will work better in certain pH levels.
What factors affect the activity of enzymes?
Enzymes work best in the pH and temperature that they are " designed " for. A pepsin enzyme works best in the low pH environment of the stomach, while amylase works best at mouth temperature and ~ 7 pH. Heat and out of range pH can denature enzymes and not only affect their activity but inactivate them.
